Art of distilling oils



Feb. 2, 1932.

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CONTINUOU UPELRHEATEQJ TILLS l E. J. SHAEFFER ET Al.

ART oF DISITILLING oIL`s Filed May 5, 17924l (Patented lfifa. 2, 1932 y,

S'MTES PATENT oFFicE EDWARD J. SHAEFFER AND EUGENE P. IBROIN, 0F WHITING, INDIANA, ASSIGNORS T0 STANDARD OIL COMPANY, OF WHITING, INDIANA, A CORPORATION 0F INDIANA ART` F DISTILLING OILS applicati@ med may 5, 1924. serial No. 711,129.

rlhe present application relates to improvements in the art of distilling o1ls, and more particularly Lin the continuous distillation of such oils wherein ythe greater pros portion of the oils are removed by substanlo which ent process and Fig. 2 is a sectional view on the line 201? the still of Fig. l.

Fig. 3 is a perspective view oi' a perforated pipe employed with the apparatus. K

Referring more particularly to the drawings, the numeral 5 indicates a still'which may suitably be the last member or" a battery of continuous stills of the usual type, in which the oil is subjected'to distillation by re and steam either with or without the aid of vacuum, as desired. From 'the still 5 the residue of the continuous distillation is drawn on through the valved pipe 5' by. a surge pump .7 or other suitable pumping device through pipe 8 into and through the heating coil 9 (diagrammatically shown) 3G mounted in a suitable furnace setting 10. lli

desired, steam or other inert gas may be introduced into the oil in the coil through pipe 8a. From the coil 9 the oil passes through a pipe 1l into an enlarged chamber 12.l which may suitably be o the form of a horizontal cylindrical shell.

Steam or other inert vapor from a supply line 13l passes through a superheating coil ifi, which may suitably be mounted in the heating coil setting 10, and from the superheater, the steam or other vapor passes through pipe 15 into the coil 16, which lies within the shell or chamber 12. The pipes ot the coil 16 extend longitudinally of the chamber and maybe positioned near'its ire ner wall, lying against the lower half thereof. From the coil, the steam passes into a distributing pipe l? lying in the lower portion of the still near the inner wall and provided with downwardly directed perforations,

-in thev still 5.

through which the steam enters the body of oil in the still.

A body of oil is maintained in the chamber 12, its level being controlled by means of the float indicator or other suitable device indicated by the numeral 18. Residue is drawn 0E through the valve draw ofi line 19 by means of a surge pump 20, the tar being discharged through the tar line 21. H desired, a flowing oil, such as the oil condensed in the condenser 24 hereinafter referred to, may be introduced into the bottom through line 21a.

From the chamber 12 vapors pass o through a large dome and vapor line 22, which are preferably insulated to prevent substantial redux into the still. rlhe vapors pass through a series of ractionating condensers 23, 24 and 25, the condensate formed in these condensers being drawn off through a cooler 26 to a receiving tank 27. Vapors uncondensed in the last oia the fractionating condensers 25 pass out through a vapor line 28 and a Valved line 29 to a condenser 30. lf desired, vapors and steam from the condenser 25 may be drawn oile through the line 31, provided with a valve 32, by means oil a suitable biower 33 and forced through the line 34 connecting with the steam supply line 13 leading into the superheater coil 14.

ln carrying out the invention, a suitable mineral oil of the nature of crude oil, which maj.7 be a crude oil or reduced crude oil, is subjected to continuous distillation with fire. and steam in the battery of stills terminating The distillation in this manner is carried to a heavy pitch-like bottom which may be, for example, in the case of a mid-continent crude from 6 to 10% of the original crude. For example, the temperature of the oil in the final sti-ll 5 of the battery may be from 650 to 75()o F, the residue being a pi of 1G to 16 Be. and having a flash point L50" F. or higher.

The hot tar is pumped continuously by surge` pump 5" from the still 5 into and through ythe heating coil 9. The oil is pumped at high velocity through this coil, in which it is rapidly brought to a temperature above decomposing temperature, and preferably above 7 50 F., the rapid iow of the oil substantially preventing coke deposits therein. y A suitable temperature for the oil at the outlet of the coil 9 is, for example, from 775 to 825 F. 'llhe oil is not retained in the coil for a sufficient period to cause substantial decomposition thereof. From the heating coil 9 the hot oil passes through the pipe 11 into the enlarged chamber 12, which is of suilicient size to permit the oil to remain therein for a considerable period, preferably in excess of one hour. Steam is passed through the super-heating coil 14, in .which it is brought to a temperature at least as high as the temperature of the oil in the chamber 12, and preferably higher, say 900 F. to 1100 F., and is then forced through the coil 16 in the interior of the chamber 12, finally entering the distributing pipe 17 and passing into the body of oil. The high temperature steam substantially maintains the temperature lof the oil within the chamber 12 and materially aids the evaporation of the more volatile constituents of the oil formed therein. Other inert gases or vapors, such as Hue gas, natural gas, light oil vapors, etc., may be substituted for the steam, if desired. The system is maintained at substantially atmospheric pressure and an extremely rapid decomposition of the oil takes place in the enlarged chamber 12. Ordinarily, from 30 to 60% of the oil is distilled off in the form of vapors of products of decomposition, leaving a tar which, in the case of a mid-continent crude as above referred to, may be from 3 to 5% of the original crude. This tar is drawn off substantially continuously through the draw oif pipe 19, for example, by the surge pump 20. The tar dra-wn of may be mixed off with a hot and lighter oil, if desired, such as the condensate from the tower 24 and disposed of as fuel.

The vapors evolved from the oil in the chamber 12, together with the steam discharged thereinto, pass 0H rapidly through the vapor line 22, which is preferably insulated and so arranged as to avoid any substantial reflux into the chamber 12.

The vapors passing out of the still 12 .travel successively through the fractionating condensers 23, 24 and 25, which are illustrated as being of a standard air-cooled type, but may be of any desired form. The successive fractions condensed in these fractionating condensers are removed through the cooling worms 26, passing into the receiving tanks 27. The operation of the fractionating condensers may be controlled in accordance with the characteristics of the vdesired products. For example, it has been found convenient to cool the vapors in the first condenser 23 to 600 to 650 F.; in the condenser 24 to 500 t0 550 F.; and in the condenser 25 to an temperature of condensation of the steam.

aeeaeao lin so operating, a condensate of the characterof heavy oil may be formed in and removed from the condenser 23; a product of the character of gas oil in the condenser 24 and a kerosene-like product in the condenser 25. rlhe vapors uncondensed in the last aerial condenser may pass through the lines 28 and 29 into the condenser 30, in which they may be condensed, forming gasoline-like and kerosene-like products. If desired the vapors issuing from the last fractionating condenser 25 may be forced by the blower 83 into the steam supply line 13 leading into the superheating coil 14. As these vapors consist largely of steam, the latent heat of the steam and vapors thus reused is saved in this manner of operation.

v In general, the present method of operation is applicable in connection with processes of continuous distillation in which crude oils are reduced by non-cracking distillatory methods to heavy pitch bottoms of the order of 10 to 16 Baume, or heavier. Although illustrated in connection with the treatment of mid-continent oils, it is readily apparent that it may be employed in the treatment of any type of crude oil or oil of similar nature, as reduced crude oil, from which the utmost recovery of valuable products is desired. The decomposed tar drawn from the enlarged chamber 12, in which theV greater part of the decomposition of the oil takes place, has a relatively low viscosity as compared with a product bearing a like relation to the original crude oil and obtained directly by steam and fire distillation, and consequently may be directly employed as a fluid fuel. rlhe specific details of the process above set forth are not intended to be regarded as limitations upon the scope of the invention, except insofar as included in the accompanying claims.

We claim:

1. The method of distilling oils which consists in subjecting a crude oil to distillation under substantially non-cracking conditions to form a residue of a pitch-like character, forcing said residueA from `the distillation zone directly through a heating coil in a rapidly flowing stream, said coil being externally heated to impart to the residue oil a temperature of at least 750 F. Without substantial decomposition thereof, passing the heated residue oil products from said heating coil into an enlarged chamber in which a body of unvaporized liquid is held and, wherein its temperature is substantially maintained, the unvaporized residue products being maintained in said chamber until a material decomposition thereof is effected, forcing an independent stream of heated inert gas through the liquid in said enlarged y chamber, thereby aiding the removal of vasuitable temperature, preferably above the` pors of products of decomposition, drawmg olf said vapors and inert gas and sepaof the oil to above decomposing temperature,

and passing the heated liquid oil directly into an enlarged chamber maintained approximately at atmospheric pressure, applying heat interiorly of the enlarged chamber to maintain the temperature of the oil therein at above cracking temperature, passing super-heated steam' into said oil, thereby aiding in the removal of vapors of products of decomposition, a body of residue oil being retained in said enlarged chamber until a material decomposition is effected, removing and fractionally condensing the vapors evolved in said enlarged chamber, and separately removing the liquid residuum therefrom.

3. The method of distilling oils which comprises reducing a crude oil by means of fire and steam to a heavy residue, said residue having a temperature of approximately 700o F. in the distilling zone, removing said residue and applying heat thereto while in a. rapidly flowing stream to bring said residue oil to a temperature of 800 F. or higher passing said heated residue oil into an enlarged chamber, maintaining the temperature of the liquid therein by interiorly applied heat, a material decomposition of said residue oil body taking place in the enlarged chamber, passing superheated steam into said oil body, thereby aiding the removal of vapors of products of decomposition, fractionally condensing said vapors, and removing the tar from said enlarged chamber.

4. The method of distilling oils which con- `sists in subjecting a crude petroleum oil to distillation under substantially non-cracking conditions to form a residue of a pitchlike character, forcing said residue from the distillation zone directly through a heating coil in a rapidly flowing stream, said coil being heated to impart to the residue oil a temperature above decomposing temperature without substantial decomposition thereof, passing the liquid residue oil from said heating coil into an enlarged chamber in which a body of said residue is maintained until a material decomposition thereof is effected, superheating steam to a temperature at least as high as that of the oil in said chamber, passing the steam through a closed passage within the chamber in indirect heat conductive contact with the oil therein, thereby maintainimY the temperature of said oil, subsequently oil within said chamber, and maintaining substantially atmospheric pressure in the chamber.

5. The method of distilling a heavy, pitchlike residue from the substantially non-cracking distillation of crude petroleum oil which comprises forcing said residue, previously heated to a. temperature of at least 650 F.. through a heating coil in a rapidly flowing stream, said coil being heated to impart to the residue oil a temperature above decomposing temperature without substantial decomposition thereof, passing the heated oil from said heating coil into an enlarged chamber, in which a body of said oil is maintained, superheating steam to a temperature at least as high as that of the oil in said chamber, passing the heated steam in a closed passage within said chamber in indirect heat conductive contact with the oil therein, thereby maintaining the temperature of the latter while decomposition thereof is effected, and subsequently discharging the steam into said body of oil.

6. rlhe method of distilling a heavy, pitchlike residue from the substantially non-cracking distillation of crude petroleum oil which i discharging the steam into said from said heating coil into an enlarged chamber, in which a body of said oil yis maintained, superheating steam to a temperature at least as high as that of the oil in said chamber, passing the heated steam in a closed passage within said chamber in indirect heat conductive contact with the oil therein,therebymain taining the temperature of the latter while decomposition .thereof is effected, and subsequently discharging the steam into said body of oil, while maintaining substantially atmospheric pressure lin said chamber.

7. The method of distilling a heavy, pitchlike'residue derived from the substantially non-cracking 'distillation of crude petroleum oil which comprises passing such residue, previously heated to liquefaction temperature, through a heating zone in a rapidly flowing stream, wherein the residue oil is brought to a temperature above decomposing -'temperature without substantial decomposition thereof, passing the heated residue oil directly into an enlarged chamber in which a body of oil is maintained, applying heat interiorly of the enlarged chamber to maintain the temperature of the oil therein at above decomposition temperature a material decomposition of the oil being eected therein,

and passing steam into the body of oil. in the chamber.

8. The method of distillin a heavy, pitchlike residue derived from. t e substantially non-cracking distillation of crude petroleum oil which comprises passing such residue, previously heated to liquefaction temperature, through a heating zone in a rapidlyl flowing stream, wherein the residue oil is brought to a tem erature above decomposing temperature Wit rout /substantial decomposition thereof, passing the heated residue oil directly into an enlarged chamber in Which a body of oil is maintained, applying heat interiorly of the enlarged chamber 'to maintain the temperature of the oil therein at above decomposition temperature, a material decomposition of the oil being eected therein, and passing steam into the body of oil in the chamber, While maintaining substantially atmospheric ressure in said chamber.

* DWARD J'. SHAEFFER.

EUGENE l?. BRUWN. 

